for Highway Construction Page 551 of 715 SECTION 632 – REMOVAL OF BRIDGE DECK CONCRETE
632.01 Description.
Remove defective concrete and/or contaminated concrete from the upper portions of bridge deck s as specified. Removal does not include full depth deck removal, unless required as Class B or surface preparation beyond that which is incidental to the removal process. On completion of removal, the Engineer will inspect the deck to determine if further removal is required. Temporarily plug bridge drains to prevent waste materials from entering the drainage system. Protect expansion joints and barrier curbs from damage. Class A removal is the removal of concrete from the deck top surface specified and to the mean depth limits specifie d. Use hydrodemolition or mechanical means after the seal coat has been removed. If the hydrodemolition removal extends beyond the mean removal depth where unsound concrete is encountered, the Department will still consider the work Class A removal at no additional cost to the Department. Remove concrete, not removed to specified limits during hydrodemolition, by mechanical means. If less than an entire continuous slab is to undergo Class A removal, saw cut the line separating where it is required and the section where removal is not required, before removal of concrete, to a depth of approximately 75 percent of the planned removal depth. Class B removal is the removal of concrete after completion of Clas s A removal and as directed.
632.02 Materials.
None specified.
632.03 Construction Requirements.
Before starting deck remo val, obtain Department approval of the concrete mix design for the new deck
A.Class A Removal.
1.Mechanical Removal. Perform mechanical removal using power -operated diamond grinding machinery or by the use of 30- pound maximum jackhammers operated at a 45° angle or less from the surface of the slab. If reinforcing steel is exposed in the course of this class of removal, immediately stop work and request instructions from the Engineer.
2.Hydrodemolition Removal
a.Concrete Removal. The Engineer will designate a trial area for the Contractor to show the equipment, personnel, and methods of operation are capable of producing satisfactory results. The Engineer will set parameters for the removal of the concrete. Begin work upon Engineer acceptance of the trial results area.
b.Completely clean exposed steel of rust, scale, and corrosion. Repair reinforcing steel that is damaged or broken with an approved procedure at no additional cost to the Department as specified in 502.03.E.
c.Equipment. Use hydrodemolition equipment that is self -propelled with a high- pressure water jet stream capable of removing concrete to the specified depth and capable of removing rust and concrete particles from reinforcing steel . Use hand -held, high- pressure wands or 30- pound for Highway Construction Page 552 of 71 5 maximum jackhammers operated a 45° angle or less from horizontal in areas that are inaccessible to the self -propelled machine.
d.During the start -up of hydrodemolition, have a qualified full -time employee of the hydrodemolition equipment manufacturer onsite until the removal operation is progressing satisfactorily. Ensure the representative remains available for the hydrodemolition work. Adhere to the manufacturer’s written instructions and/or recommendations made by the representative, on or off the project site, at no additional cost to the Department. The cost of the manufacturer’s representative is incidental .
e.Provide documentation to show that only qualified personnel, trained by the equipment manufacturer, operate equipment. Provide sufficient spare parts and service to maintain the equipment operation.
f.Provid e shielding to ensure containment of dislodged material within the removal area. Protect the public from flying debris on and under the project site.
g.Runoff. Collect runoff water and residual material within existing roadway slopes, then dispose by land ap plication offsite. Line temporary collection ponds with a separation geotextile. Do not allow runoff water or residual material to flow into the vehicular or pedestrian traffic areas or nearby waterways. Obtain required permits and compl y with applicable regulations concerning water disposal.
h.Cleaning. Perform cleaning, before debris and water dry on the surface, with a vacuum system or other method capable of removing wet debris and water in the same pass. Blow -dry the deck with air to remove excess debris and water. Adequately support exposed reinforcing steel that is left unsupported by the hydrodemolition process and protect the steel from construction operations.
B.Class B Removal . After the Class A removal has been completed, the Engineer will check for delamination in accordance with ASTM D4580 and resound or chain the deck to verify unsound material has been removed. Perform additional removal, designated as Class B, with the hand- held hydro- wand, or 30- pound maximum jackhammer operated at an angle of 45° or less from horizontal, or by the use of hand tools. If the bond between concrete and reinforcing steel has been destroyed, remove the adjacent concrete to a depth that will provide a minimum ¾ inch clearance around the steel. Clean before debris and water dries on the surface. Adequately support exposed reinforcing steel that is left unsupported and protect the steel from construction operations. As with Class A removal, exercise control of debris and wash residual. Protect areas below the bridge and as directed.
632.04 Method of Measureme nt.
The Engineer will measure acceptably completed work by the square yard based on planned quantity for Class A and measured quantity for Class B.
632.05 Basis of Payment .
The Department will pay for accepted quantities at the contract unit prices as follows: for Highway Construction Page 553 of 715 Pay Item Pay Unit Concrete Bridge Deck Removal Class A ................................................ SY Concrete Bridge Deck Removal Class B ................................................ SY for Highway Construction Page 554 of 715 SECTION 633 - RESERVED
Source: Idaho Standard Specifications for Highway Construction, 2023 Edition. Pages 587–589 of 768.